Transducer, transduction apparatus, and terminal

Abstract

A transducer, a transduction apparatus, and a terminal are provided, and belong to the field of device technologies. The transducer includes a substrate layer, a first electrode layer, a piezoelectric layer, a second electrode layer, a first protective layer, and a second protective layer that are sequentially arranged. A sum of target parameters of the piezoelectric layer, the second electrode layer, the first protective layer, and the second protective layer is a positive integer multiple of n, where 0.1≤n≤0.4. A target parameter of at least one of the film layers in the transducer is a ratio of a thickness of the at least one film layer to a wavelength of a sound wave at an operating frequency of the transducer when the sound wave is transmitted at the at least one film layer.

What is claimed is: 
     
         1 . A transducer, comprising a sequential arrangement of film layers comprising the following film layers:
 a substrate layer;   a first electrode layer;   a piezoelectric layer;   a second electrode layer;   a first protective layer; and   a second protective layer, wherein:
 materials of the first protective layer and the second protective layer are different; 
 a sum of target parameters of the piezoelectric layer, the second electrode layer, the first protective layer, and the second protective layer is a positive integer multiple of n, where 0.1≤n≤0.4; and 
   a target parameter of at least one of the film layers in the transducer is a ratio of a thickness of the at least one film layer to a wavelength of a sound wave at an operating frequency of the transducer when the sound wave is transmitted at the at least one film layer.   
     
     
         2 . The transducer according to  claim 1 , wherein a sum of target parameters of the substrate layer, the first electrode layer, the piezoelectric layer, the second electrode layer, the first protective layer, and the second protective layer is a positive integer multiple of n. 
     
     
         3 . The transducer according to  claim 1 , wherein the transducer further comprises a second additional layer, a third additional layer, and a fourth additional layer;
 the fourth additional layer, the third additional layer, the second additional layer, the substrate layer, the first electrode layer, the piezoelectric layer, the second electrode layer, the first protective layer, and the second protective layer are sequentially arranged; and   a sum of target parameters of the third additional layer, the second additional layer, the substrate layer, the first electrode layer, the piezoelectric layer, the second electrode layer, the first protective layer, and the second protective layer is a positive integer multiple of n.   
     
     
         4 . The transducer according to  claim 3 , wherein a material of the second additional layer comprises an adhesive, a material of the third additional layer comprises copper, and a material of the fourth additional layer comprises an adhesive. 
     
     
         5 . The transducer according to  claim 1 , wherein:
 an acoustic impedance of the piezoelectric layer is greater than twice an acoustic impedance of the second electrode layer; or   an acoustic impedance of the piezoelectric layer is less than one half of an acoustic impedance of the second electrode layer; and   the target parameter of the second electrode layer is less than one tenth.   
     
     
         6 . The transducer according to  claim 1 , wherein:
 the acoustic impedance of the piezoelectric layer is greater than twice an acoustic impedance of the second protective layer; or   the acoustic impedance of the piezoelectric layer is less than one half of an acoustic impedance of the second protective layer; and   the target parameter of the second protective layer is less than one tenth.   
     
     
         7 . The transducer according to  claim 1 , wherein a material of the first protective layer comprises an adhesive and a material of the second protective layer comprises metal. 
     
     
         8 . The transducer according to  claim 1 , wherein the first protective layer is obtained by superposing a plurality of layers of structures. 
     
     
         9 . The transducer according to  claim 8 , wherein the first protective layer comprises two first polymer layers and a second polymer layer superposed between the two first polymer layers, and hardness of the second polymer layer is greater than hardness of the first polymer layer. 
     
     
         10 . The transducer according to  claim 1 , wherein the transducer meets at least one of the following conditions:
 the first electrode layer comprises a plurality of first electrode blocks arranged in an array;   the second electrode layer comprises a second electrode block;   an orthographic projection of the second electrode block at the substrate layer and an orthographic projection of the piezoelectric layer at the substrate layer have an overlapping region; and   orthographic projections of the plurality of first electrode blocks at the substrate layer are located in the overlapping region;   the transducer further comprises a circuit layer located between the substrate layer and the first electrode layer, and the circuit layer is connected to the first electrode layer; and   the transducer further comprises an auxiliary adhesion layer located between the first electrode layer and the piezoelectric layer.   
     
     
         11 . The transducer according to  claim 1 , wherein a material of the substrate is glass, silicon, or a polymer material. 
     
     
         12 . The transducer according to  claim 1 , wherein a material of the piezoelectric layer is an organic polymer material or an inorganic piezoelectric material. 
     
     
         13 . The transducer according to  claim 1 , wherein the operating frequency of the transducer ranges from 5 megahertz to 25 megahertz. 
     
     
         14 . The transducer according to  claim 1 , wherein the wavelength of the sound wave at the operating frequency of the transducer when the sound wave is transmitted at the at least one film layer is:
 a ratio of a longitudinal wave sound velocity of the sound wave at the operating frequency of the transducer when the sound wave is transmitted at the at least one film layer to a frequency of the sound wave at the operating frequency of the transducer; or   a ratio of a transverse wave sound velocity of the sound wave at the operating frequency of the transducer when the sound wave is transmitted at the at least one film layer to a frequency of the sound wave at the operating frequency of the transducer; or   a ratio of a guided-wave sound velocity of the sound wave at the operating frequency of the transducer when the sound wave is transmitted at the at least one film layer to a frequency of the sound wave at the operating frequency of the transducer.   
     
     
         15 . A transduction apparatus, comprising:
 a controller; and   a transducer comprising a sequential arrangement of film layers comprising the following film layers:
 a substrate layer; 
 a first electrode layer; 
 a piezoelectric layer; 
 a second electrode layer; 
 a first protective layer; and 
 a second protective layer, wherein:
 materials of the first protective layer and the second protective layer are different; 
 a sum of target parameters of the piezoelectric layer, the second electrode layer, the first protective layer, and the second protective layer is a positive integer multiple of n, where 0.1≤n≤0.4; and 
 
 a target parameter of at least one of the film layers in the transducer is a ratio of a thickness of the at least one film layer to a wavelength of a sound wave at an operating frequency of the transducer when the sound wave is transmitted at the at least one film layer, wherein: 
   the controller is configured to provide a first electrical signal to the transducer; and   the transducer is configured to emit a first sound wave based on the first electrical signal.   
     
     
         16 . The transduction apparatus according to  claim 15 , wherein:
 the transducer is further configured to receive a second sound wave and to provide a second electrical signal to the controller based on the second sound wave; and   the controller is configured to generate an image based on the second electrical signal.   
     
     
         17 . The transduction apparatus according to  claim 15 , wherein a second protective layer in the transducer is an electrically grounded conductor. 
     
     
         18 . The transduction apparatus according to  claim 15 , wherein:
 a second protective layer in the transducer is a conductor;   the transduction apparatus further comprises a switch;   the second protective layer is grounded via the switch; and   the controller is configured to control the switch to be turned off in a phase in which the transducer emits the first sound wave and to be turned on in a phase in which the transducer receives the second sound wave.   
     
     
         19 . The transduction apparatus according to  claim 18 , wherein:
 the transducer comprises a second additional layer, a third additional layer, and a fourth additional layer, and the fourth additional layer, the third additional layer, the second additional layer, the substrate layer, the first electrode layer, the piezoelectric layer, the second electrode layer, the first protective layer, and the second protective layer are sequentially arranged;   a sum of target parameters of the third additional layer, the second additional layer, the substrate layer, the first electrode layer, the piezoelectric layer, the second electrode layer, the first protective layer, and the second protective layer is a positive integer multiple of n; and   both the second additional layer and the fourth additional layer are insulated, the third additional layer is a conductor, and the third additional layer is grounded via the switch.   
     
     
         20 . A terminal, comprising a sequential arrangement of film layers comprising the following film layers:
 a substrate layer;   a first electrode layer;   a piezoelectric layer;   a second electrode layer;   a first protective layer; and   a second protective layer, wherein:
 materials of the first protective layer and the second protective layer are different; 
 a sum of target parameters of the piezoelectric layer, the second electrode layer, the first protective layer, and the second protective layer is a positive integer multiple of n, where 0.1≤n≤0.4; and 
   a target parameter of at least one of the film layers in the transducer is a ratio of a thickness of the at least one film layer to a wavelength of a sound wave at an operating frequency of the transducer when the sound wave is transmitted at the at least one film layer.